In the present state of the art a conventional motion picture projector utilizes a standard lamp housing and projects a light beam having a circular cross section onto the film gate of the projector. The conventional projector is converted to a 3D projector utilizing our POLARATOR.TM. attachment (U.S. Pat. No. 3,851,955, "Apparatus for Converting Motion Picture Projectors for Stereo Display", Dec. 3, 1974) to the standard projection lens. The POLARATOR.TM. contains polarizing elements which absorb from 60-65% of the incident light. More light is lost at the gate because the aperture plate is rectangular and the beam cross section is circular and light spills over the edge of the aperture, about 40% being wasted. Accordingly, it is an object of this invention to provide an efficient means for polarizing the light and means for conserving the light entering the gate.
FIG. 1 is a diagrammatic cross sectional illustration of an optical system in accordance with the present invention.
FIG. 2 illustrates a negative aspheric lens for minimizing light loss at the film gate.
FIG. 3 illustrates an oval shaped cross section of a light beam at the film gate.
FIG. 4 shows an elliptical beam on a rectangular film gate aperture and an oval shaped beam to minimize light loss; and
FIG. 5 shows a standard film gate aperture inscribed within a circular light beam which has considerable light loss.